Coffee First Crack Prediction Calculator
Created by: Olivia Harper
Last updated:
Estimate when first crack will begin using live roast trajectory inputs.
First Crack Prediction Calculator
CoffeeEstimate first crack timing from live roast trajectory
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What is a First Crack Prediction Calculator?
Anticipating key roast transitions
A first crack prediction calculator estimates when first crack is likely to occur using current roast trajectory data.
This supports better phase transitions and smoother development planning.
Planning ahead reduces reactive control moves that can destabilize ROR late in the roast. It also improves consistency when multiple operators share profiles.
Prediction Formula
Trajectory-based time-to-event model
Minutes to First Crack = (Target First Crack Temp - Current Bean Temp) ÷ Current ROR
The base estimate is adjusted by bean-type offset to reflect practical roast behavior differences.
Because ROR changes through the roast, this estimate should be refreshed as trajectory stabilizes. Frequent recalculation improves decision timing.
Example
Live checkpoint estimate
If current bean temp is 165°C and current ROR is 12°C/min with a first crack target of 196°C, base estimate is about 2.6 minutes.
Bean-type offset then shifts this baseline to reflect expected process behavior. That creates a more practical cue for control staging.
Applications
Control planning and training
Use this tool for profile rehearsal, heat-step timing, and roast assistant decision support.
It is also useful for training newer operators to recognize how live momentum influences event timing.
Tips
Improve prediction reliability
Log predicted versus actual first crack times for each lot and profile family. This feedback loop helps you tune offsets and improve future forecasts.
ROR often changes quickly near yellowing and Maillard. Recalculate as your trajectory stabilizes.
Track prediction error over multiple lots to calibrate your roaster-specific offset.
Frequently Asked Questions
What is first crack prediction?
It estimates when first crack will begin based on charge temperature, early roast momentum, and bean type behavior. This gives roasters more time to stage heat and airflow changes before development starts.
Is this a replacement for cupping and sensory checks?
No. Use it as a planning aid, then validate with live roast observations and profile data. Sensory evaluation remains essential for confirming whether the predicted timing supports your target cup profile.
Why does bean type matter?
Different processes and density profiles shift how quickly beans absorb heat and approach first crack. Including bean type helps convert a generic projection into a more practical production estimate.
How should I use the output?
Use predicted first crack time to pre-plan heat and airflow changes before development starts. Re-check prediction as the roast progresses so control actions stay aligned with live momentum.
Sources and References
- SCA roasting education references on crack timing and development control.
- Professional roast logging workflows for ROR and event prediction.